Although many new web-based crime mapping solutions have been developed and are available in the market, there are only very few studies focusing on web-based crime mapping. On the basis of a review of the police agencies in the world's top 100 highest GDP cities, nine major types of web-based crime mapping functions are summarized. Furthermore, we also found that three predictors – number of employees, range of computerized information used and recruit training hours – are positively correlated with the extent of web-based crime mapping adoption, in which recruit training hours is the most influential predictor. This finding might indicate that if a policymaker wishes a police agency to adopt a wider extent of web-based crime mapping, promoting a positive culture of policing service might be more effective than simply assigning more budget and manpower to police agencies. We believe that this is the first time that a study like this has been conducted to review and to discuss the trend and predictors of web-based crime mapping adoption.